We cooked a Mercury today, did you?

[redfury]

Re: We cooked a Mercury today, did you?

I have to agree. There's a good chance that there won't be much you can point to the mechanic being at fault.

The thought of it running lean though has merit. My lawn tractor runs AWESOME, but only when I'm running the last bit of fuel out of the carb after I've run out of gas ( lean ). Running lean means running hot, and on an outboard, running lean means running with too little lubrication. If the motor has that few hours on it, you shouldn't have much if any fluctuation in compression between cylinders. I'd be unhappy with more than 2-3% from top to bottom if it was well taken care of after the rebuild.

 

[halmc]

Re: We cooked a Mercury today, did you?

Oh and let me tell you, my dad is PISSED. He had a new water pump installed 3 weeks ago

Put it in the water, see what happens. If it runs OK, your overheating might have been caused by a plastic bag or other obstruction. If it starts to overheat, but otherwise runs OK, take it to a different "mechanic" and have the water pump replaced correctly, or better yet, do it yourself. Take a casual look at the mechanic and decide whether you think you can master any task he can master. And then some. Incidentally, that ten psi variation in the compression check is nothing. And never pull the head on an engine that doesn't have one.

If the engine doesn't run well, i.e., if there's damage that prevents it from running well, consign it to the landfill and lick your wounds. The court system doesn't work all that well when it is resolving multi-million dollar lawsuits among major corporations much less when it's called upon to sort out differences arising from the errant repair of an aging outboard motor. When you enter small claims division behind all the housewives with their broken or impotent vacuum cleaners who too are waiting behind all the folks who hired lawyers to see the judge, you'll get my point. If I still had my office (I have a five digit Fla. Bar number issued in 1973), and if you walked in to get me to represent you, I'd want $5k up front to take your case. That's because it's as much trouble to deal with this sort of case as it is a moderately appalling felony.

Taking it back to the same "mechanic" is like getting bit by the same dog twice. Shame on the dog the first time. The second time -- well, shame on you. That said, the mechanic who may have been dumb enough to booger a water pump installation will invariably be smart enough to claim that you mistreated it.

Luck's a fickle lady. Test it. If it works, you're home free. If it works but doesn't pump water, there's hope. If it sounds like a bunch of bolts being shaken up in a Luzianne coffee can, either take it to the land fill or donate it to your local PBS station.

 

[waterinthefuel]

Re: We cooked a Mercury today, did you?

Yes, it was working fine for the few minutes it took us to reach our fishing spot. It was when we really showered down on in that it went out.

Against my advice, my dad brought it back to the same mechanic. He pulled the lower unit and found that two things had occurred. The bottom plates for the water pickup on the side of the lower unit were loose allowing debris in, and also, he found what looked like wood shavings of some sort inside the impeller housing. He said the impeller was in great condition, however. He bore scoped the engine and said it looks beautiful, the engine is in fantastic condition. I asked about the filings and he said that a piston guide or something (don't quote me on that) could make that, but there is zero scarring inside the cylinder so no damage occurred. He did a leak test, whatever that is, and said that there is less than 2 percent on each cylinder, so that shows nothing is wrong internally. He also started it and said the water pump is producing the correct amount of water pressure, so it's fine too.

All in all, it looks like we got lucky. I don't like where the tattle tale comes out of that engine, as I can't see it from where I sit and my dad, the usual driver, is too busy driving to turn around 180 and look. We will change our methods and might even modify the engine so it shoots out where you can see it better.

 

[j_martin]

Re: We cooked a Mercury today, did you?

I don't have any idea what a "piston guide" is. Leakdown is a one-up on a compression test. It measures the rate that air pressure leaks past the pistons when they're positioned about halfway between top dead center and the ports. 2 percent sounds fantastic, maybe unbelievable.

I cut a rotten log in two with the XR4 once. Picked toothpicks out various places in the cooling system for a month. Gummed it up pretty good, but the pressure gauge and overtemp alarm clued me in so no damage was done.

If you're going to drive it in the tuliweeds and maybe get some crap in the water pickup, it would be well worth your while to put a water pressure gauge on that engine.

John

 

[rwunstel]

Re: We cooked a Mercury today, did you?

Yes, it was working fine for the few minutes it took us to reach our fishing spot. It was when we really showered down on in that it went out.

Against my advice, my dad brought it back to the same mechanic. He pulled the lower unit and found that two things had occurred. The bottom plates for the water pickup on the side of the lower unit were loose allowing debris in, and also, he found what looked like wood shavings of some sort inside the impeller housing. He said the impeller was in great condition, however. He bore scoped the engine and said it looks beautiful, the engine is in fantastic condition. I asked about the filings and he said that a piston guide or something (don't quote me on that) could make that, but there is zero scarring inside the cylinder so no damage occurred. He did a leak test, whatever that is, and said that there is less than 2 percent on each cylinder, so that shows nothing is wrong internally. He also started it and said the water pump is producing the correct amount of water pressure, so it's fine too.

All in all, it looks like we got lucky. I don't like where the tattle tale comes out of that engine, as I can't see it from where I sit and my dad, the usual driver, is too busy driving to turn around 180 and look. We will change our methods and might even modify the engine so it shoots out where you can see it better.

I don't know what a piston guide is, but if he meant locater pin or ring guide, then you better not run it. The ring will end up in the exhaust port and do considerable damage. Replace the piston if that is what he was talking about. Piston locater pins and the piston itself are two different materials. The over heating of the piston will cause the piston to expand. The piston is made of alumiumn and the locater pin is steel. They expand and contract at different levels. The pin will become loose and come out. Thats when the trouble starts. If the pin gets on top of the piston it will beat the heads and pistons and cause the small amounts of aluminum you seen on your plugs. The pin just beats around on top and could chip small amounts of aluminum out of your heads or pistons. Then the ends of your rings will work around and break off as the ends spring open into the exhaust posts. They will start to break of and then big problems start to happen.

 

[j_martin]

Re: We cooked a Mercury today, did you?

If there's any metal at all on a plug, it came from somewhere, and I don't know of any metal in the cylinder that is not needed.

I'd tear it down and find out. If all is good you put in new gaskets. If there's a locator pin loose in a piston, you replace the piston and don't grenade the powerhead.


hope it helps
John

 

[ddrieck]

Re: We cooked a Mercury today, did you?

The metal and the grayish look of the spark plug you are refering to can be from only one thing. The cylinder tempurature has gotten to high from one of three things:

1. Lack of lubrication(inproper oil mix)
2. Lean condition(carburation problem)
3. Lack of cooling(inpeller/waterpump problem).

With that being said the metal/grayish plug is the aluminum starting to melt of the top of the piston in trace amounts.

 

[BF]

Re: We cooked a Mercury today, did you?

4. Timing set too far advanced.

It's also possible that more than 1 of these things could combine just enough to go past the ragged edge.

 

[ddrieck]

Re: We cooked a Mercury today, did you?

Forgot to mention two:


#4 from above---incorrect ignition timing.

5. Hot Spark plugs (incorrect heat range per engine application)

Now if and it's a strong if, the engine was shut down in time with minimul damage to the top of the piston, your engine may run for a long time. However, IMO, it should be pulled apart my a compitant mechanic, the piston in question replaced, impeller/waterpump replaced, all cooling passages checked/cleaned, and the timing set.
As for going back on the initial mechanic, ita a crap shoot. If it were to go to court and a judgement awarded to you it doesnt mean that the mechanic will ever pay for or repair your engine. Not all peaople are as honest as we want them to be.....just my 2 cents